Metal oxides may be deposited as very hard thin films to act as thermal insulators on glass and other substrates or to form transparent electrodes for use with solar cells or other electo-optical devices. One method of deposting such films is by atmospheric pressure chemical vapor deposition (APCVD). In APCVD, the substrate to be coated, such as glass, is heated to an elevated temperature and exposed to a vapor containing a metal oxide precursor or a metal oxide precursor and a dopant. The vapor is thermally reacted on or near the surface of the substrate and is deposited as a metal oxide coating on the substrate.
A number of metal oxide precursors and dopant combinations are known to the prior art. Fluorine has been used as a dopant to create a hard oxide coating having high transparency as well as high conductivity. An example of such a metal oxide coating, in which there has been considerable interest, is tin oxide doped with fluorine. A method of producing this film has been to use tin tetrachloride as the metal oxide precursors, water as the oxidizing agent and hydrofluoric acid as the dopant. The tin oxide film deposited tends to be hazy and thereby may be unappealing for various (e.g. architectural) applications.
The present invention relates to various metal oxide precursors and dopants containing chemically reactive vinylic fluorine and methods which can be used to produce a uniform, substantially haze free, metal oxide film on a substrate such as glass.